EP1114484B1 - High-temperature fuel cell with a nickel network on the anode side and high-temperature fuel cell stack having said cell - Google Patents

High-temperature fuel cell with a nickel network on the anode side and high-temperature fuel cell stack having said cell Download PDF

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Publication number
EP1114484B1
EP1114484B1 EP99952294A EP99952294A EP1114484B1 EP 1114484 B1 EP1114484 B1 EP 1114484B1 EP 99952294 A EP99952294 A EP 99952294A EP 99952294 A EP99952294 A EP 99952294A EP 1114484 B1 EP1114484 B1 EP 1114484B1
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EP
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Prior art keywords
fuel cell
temperature fuel
nickel
bipolar plate
network
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EP99952294A
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German (de)
French (fr)
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EP1114484A2 (en
Inventor
Manfred Wohlfart
Wolfgang Thierfelder
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Siemens AG
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Siemens AG
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/02—Details
    • H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
    • H01M8/0204—Non-porous and characterised by the material
    • H01M8/0206—Metals or alloys
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/02—Details
    • H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
    • H01M8/0204—Non-porous and characterised by the material
    • H01M8/0215—Glass; Ceramic materials
    • H01M8/0217—Complex oxides, optionally doped, of the type AMO3, A being an alkaline earth metal or rare earth metal and M being a metal, e.g. perovskites
    • H01M8/0219—Chromium complex oxides
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/02—Details
    • H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
    • H01M8/0204—Non-porous and characterised by the material
    • H01M8/0223—Composites
    • H01M8/0228—Composites in the form of layered or coated products
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/02—Details
    • H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
    • H01M8/023—Porous and characterised by the material
    • H01M8/0232—Metals or alloys
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/02—Details
    • H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
    • H01M8/023—Porous and characterised by the material
    • H01M8/0241—Composites
    • H01M8/0245—Composites in the form of layered or coated products
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/10—Fuel cells with solid electrolytes
    • H01M8/12—Fuel cells with solid electrolytes operating at high temperature, e.g. with stabilised ZrO2 electrolyte
    • H01M2008/1293—Fuel cells with solid oxide electrolytes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2300/00—Electrolytes
    • H01M2300/0017—Non-aqueous electrolytes
    • H01M2300/0065—Solid electrolytes
    • H01M2300/0068—Solid electrolytes inorganic
    • H01M2300/0071—Oxides
    • H01M2300/0074—Ion conductive at high temperature
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30—Hydrogen technology
    • Y02E60/50—Fuel cells

Definitions

  • the invention relates to a high-temperature fuel cell, where between a bipolar plate on the Fuel gas side and a solid electrolyte a nickel network is arranged. It continues to refer to a high temperature fuel cell stack, which is a number of such Contains high temperature fuel cells.
  • the electrolyte electrode unit comprises two electrodes and one arranged between the two electrodes, Solid electrolytes designed as membranes. Thereby forms one between adjacent composite circuit boards Electrolyte electrode unit with the on both sides of the Electrolyte-electrode unit immediately adjacent contact layers a high temperature fuel cell to which also the sides of each of the contact layers belong to the two composite circuit boards.
  • This guy and further fuel cell types are, for example, from the "Fuel Cell Handbook" by A.J. Appleby and F.R. Foulkes, 1989, pages 440 to 454.
  • a high-temperature fuel cell of the type mentioned Type in which a nickel mesh is located between the anode side bipolar plate and the solid electrolyte has been designed as a product and for example in the DE 4 016 157 A1.
  • the nickel can be used as a nickel mesh package be executed that a thinner contact network and has a thicker net.
  • Chromium oxide is formed at oxygen partial pressures of less than 10 -18 bar. These partial pressures of oxygen are generally always present during the operation of the high-temperature fuel cell.
  • the nickel network has been attached to the bipolar plate by means of spot welding.
  • the welding points and also the contact points are, as it were, infiltrated by the chromium oxide during operation.
  • the object of the invention is a high-temperature fuel cell to improve the type mentioned in such a way that the increased series resistance avoided and high conductivity is also ensured over a long period of time.
  • the invention is also based on the object High temperature fuel cell stack with at least one to specify such a fuel cell.
  • the invention is based on the consideration that this is achieved can be when the formation of said chromium oxide layer can be at least largely avoided.
  • the first-mentioned object is achieved according to the invention in the aforementioned high-temperature fuel cell in that the bipolar plate made of CrFe5Y 2 O 3 1 is provided on the fuel gas side with a nickel layer, and in that the nickel network is attached to this nickel layer in an electrically conductive manner by means of a spot welding process.
  • the nickel network can consist of a nickel network package thinner nickel contact network and a thicker nickel support network his.
  • the mentioned object achieved in that the stack a large number of interconnected printed circuit boards with electrolytes in between, wherein two adjacent composite circuit boards each a high-temperature fuel cell of the type mentioned above.
  • Coating the bipolar plate with a thin layer of nickel can be done by inexpensive procedures become.
  • the process can e.g. by chemical or galvanic Separation.
  • the layer thickness should be about Amount to 20 ⁇ m.
  • the fuel gas side of the bipolar plate should be completely covered with nickel in the mesh area.
  • FIG. 1 An embodiment of the invention is described below a figure explained in more detail.
  • the figure represents a section from a high-temperature fuel cell 1.
  • a bipolar plate 2 (interconnector plate made of CrFe5Y 2 O 3 1) is provided with a number of operating device channels 4 which run perpendicular to the paper plane. These channels 4 are fed with a fuel gas, such as hydrogen, natural gas or methane.
  • the lower part of the high-temperature fuel cell 1 represents the anode side.
  • the surface 6 of the bipolar plate 2 is provided with a thin nickel layer 8. The thickness d of this nickel layer 8 is approximately 20 ⁇ m.
  • a nickel network 10 is attached to the nickel layer 8 in an electrically conductive manner by spot welding.
  • the nickel network 10 is here a nickel network package, consisting of a coarse, thicker nickel support network 10a and a fine, thinner nickel contact network 10b.
  • a solid electrolyte 12 adjoins this nickel network 10 via a thin anode 11.
  • This electrolyte 12 is delimited at the top by the cathode 14.
  • a further bipolar plate 16 with a number of operating device channels 18, only one of which is shown, is connected to the cathode 14 via a contact layer.
  • the equipment channels 18 run parallel to the paper plane. They carry oxygen or air during operation.
  • the unit consisting of cathode 14, solid electrolyte 12 and anode 11 is used as an electrolyte-electron unit (MEA) designated.
  • MEA electrolyte-electron unit
  • the nickel layer 8 shown in the figure prevents the formation a chromium oxide layer between the bipolar plate 2 and the nickel net 10 and thus ensures a constant good electrical conductivity of the contacts.
  • the fuel cell therefore has a low series resistance, which is not increased during the operating period.
  • Fuel cell stack can be summarized.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Sustainable Development (AREA)
  • Sustainable Energy (AREA)
  • Manufacturing & Machinery (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Composite Materials (AREA)
  • Materials Engineering (AREA)
  • Ceramic Engineering (AREA)
  • Fuel Cell (AREA)
  • Inert Electrodes (AREA)

Abstract

A nickel grid is arranged on the fuel-gas side of the high-temperature fuel cell, between the bipolar plate and the solid electrolyte. In order to avoid contact problems as the period of operation increases, the bipolar plate is provided with a nickel layer. The nickel grid is secured to the nickel layer in an electrically conducting manner, such as by spot welding.

Description

Die Erfindung bezieht sich auf eine Hochtemperatur-Brennstoffzelle, bei der zwischen einer bipolaren Platte auf der Brenngasseite und einem Feststoff-Elektrolyten ein Nickelnetz angeordnet ist. Sie bezieht sich weiterhin auf einen Hochtemperatur-Brennstoffzellenstapel, der eine Anzahl solcher Hochtemperatur-Brennstoffzellen enthält.The invention relates to a high-temperature fuel cell, where between a bipolar plate on the Fuel gas side and a solid electrolyte a nickel network is arranged. It continues to refer to a high temperature fuel cell stack, which is a number of such Contains high temperature fuel cells.

Es ist bekannt, daß bei der Elektrolyse von Wasser die Wassermoleküle durch elektrischen Strom in Wasserstoff (H2) und Sauerstoff (O2) zerlegt werden. In einer Brennstoffzelle läuft dieser Vorgang in umgekehrter Richtung ab. Durch die elektrochemische Verbindung von Wasserstoff (H2) und Sauerstoff (O2) zu Wasser entsteht elektrischer Strom mit hohem Wirkungsgrad: Wenn als Brenngas reiner Wasserstoff (H2) eingesetzt wird, geschieht dies ohne Emission von Schadstoffen und Kohlendioxid (CO2). Auch mit einem technischen Brenngas, beispielsweise Erdgas oder Kohlegas, und mit Luft (die zusätzlich mit Sauerstoff (O2) angereichert sein kann) anstelle von reinem Sauerstoff (O2) erzeugt eine Brennstoffzelle deutlich weniger Schadstoffe und weniger Kohlendioxid (CO2) als andere Energieerzeuger, die mit fossilen Energieträgern arbeiten. Die technische Umsetzung des Prinzips der Brennstoffzelle hat zu unterschiedlichen Lösungen, und zwar mit verschiedenartigen Elektrolyten und mit Betriebstemperaturen zwischen 80 °C und 1000 °C, geführt.It is known that in the electrolysis of water, the water molecules are broken down into hydrogen (H 2 ) and oxygen (O 2 ) by electric current. In a fuel cell, this process takes place in the opposite direction. The electrochemical connection of hydrogen (H 2 ) and oxygen (O 2 ) to water creates electrical current with high efficiency: If pure hydrogen (H 2 ) is used as the fuel gas, this happens without emission of pollutants and carbon dioxide (CO 2 ). Even with a technical fuel gas, such as natural gas or coal gas, and with air (which can also be enriched with oxygen (O 2 )) instead of pure oxygen (O 2 ), a fuel cell generates significantly fewer pollutants and less carbon dioxide (CO 2 ) than others Energy producers who work with fossil fuels. The technical implementation of the principle of the fuel cell has led to different solutions, namely with different types of electrolytes and with operating temperatures between 80 ° C and 1000 ° C.

In Abhängigkeit von ihrer Betriebstemperatur werden die Brennstoffzellen in Nieder-, Mittel- und Hochtemperatur-Brennstoffzellen eingeteilt, die sich wiederum durch verschiedene technische Ausführungsformen unterscheiden. Depending on their operating temperature, the Fuel cells in low, medium and high temperature fuel cells divided, which are in turn different distinguish technical embodiments.

Bei dem aus einer Vielzahl von Hochtemperatur-Brennstoffzellen sich zusammensetzenden Hochtemperatur-Brennstoffzellenstapel (in der Fachliteratur wird ein Brennstoffzellenstapel auch "Stack" genannt) liegen unter einer oberen Verbundleiterplatte, welche den Hochtemperatur-Brennstoffzellenstapel abdeckt, der Reihenfolge nach wenigstens eine Verbundleiterplatte eine Schutzschicht, eine Kontaktschicht, eine Elektrolyt-Elektroden-Einheit, eine weitere Kontaktschicht, eine weitere Verbundleiterplatte, usw.With a large number of high-temperature fuel cells assembling high temperature fuel cell stack (In the specialist literature there is a fuel cell stack also called "stack") are under an upper composite circuit board, which is the high temperature fuel cell stack covers, in order at least one composite circuit board a protective layer, a contact layer, an electrolyte electrode unit, another contact layer, one further composite circuit board, etc.

Die Elektrolyt-Elektroden-Einheit umfaßt dabei zwei Elektroden und einen zwischen den beiden Elektroden angeordneten, als Membran ausgeführten Festkörperelektrolyten. Dabei bildet jeweils eine zwischen benachbarten Verbundleiterplatten liegende Elektrolyt-Elektroden-Einheit mit den beidseitig an der Elektrolyt-Elektroden-Einheit unmittelbar anliegenden Kontaktschichten eine Hochtemperatur-Brennstoffzelle, zu der auch noch die an den Kontaktschichten anliegenden Seiten jeder der beiden Verbundleiterplatten gehören. Dieser Typ und weitere Brennstoffzellen-Typen sind beispielsweise aus dem "Fuel Cell Handbook" von A. J. Appleby und F. R. Foulkes, 1989, Seiten 440 bis 454, bekannt.The electrolyte electrode unit comprises two electrodes and one arranged between the two electrodes, Solid electrolytes designed as membranes. Thereby forms one between adjacent composite circuit boards Electrolyte electrode unit with the on both sides of the Electrolyte-electrode unit immediately adjacent contact layers a high temperature fuel cell to which also the sides of each of the contact layers belong to the two composite circuit boards. This guy and further fuel cell types are, for example, from the "Fuel Cell Handbook" by A.J. Appleby and F.R. Foulkes, 1989, pages 440 to 454.

Eine Hochtemperatur-Brennstoffzelle der eingangs genannten Art, bei der ein Nickelnetz zwischen der anodenseitig gelegenen bipolaren Platte und dem Feststoff-Elektrolyten angeordnet ist, ist als Produkt ausgeführt worden und belspielsweise in der DE 4 016 157 A1 beschrieben. Das Nickel kann dabei als Nickelnetzpaket ausgeführt sein, das ein dünneres Kontaktnetz und ein dickeres Tragnetz besitzt.A high-temperature fuel cell of the type mentioned Type in which a nickel mesh is located between the anode side bipolar plate and the solid electrolyte has been designed as a product and for example in the DE 4 016 157 A1. The nickel can be used as a nickel mesh package be executed that a thinner contact network and has a thicker net.

Bei einer solchen Hochtemperatur-Brennstoffzelle wurde bisher eine direkte Kontaktierung zwischen dem Nickelnetz (oder Nikkelnetzpaket) auf der einen Seite und der bipolaren Platte (Interkonnektorplatte) aus CrFe5Y2O3l auf der anderen Seite gewählt. Versuche haben nun gezeigt, daß sich auf der Brenngasseite schon nach kurzer Betriebsdauer ein erhöhter Serienwiderstand einstellt. Dieses besagte Nickelnetz dient auf der Brenngasseite (Anodenseite) der Hochtemperatur-Brennstoffzelle als Kontaktierung zwischen der bipolaren Platte und dem Feststoff-Elektrolyten. Die Versuche haben nun ergeben, daß bei der direkten Verbindung zwischen dem Nickelnetz und der Interkonnektorplatte schon nach kurzer Zeit eine Zwischenoxidschicht auftritt, die sich im wesentlichen aus Chromoxid zusammensetzt. Da diese Chromoxid-Schicht einen höheren Widerstand als die eingesetzten Metalle besitzt, wird der Anstieg des Serienwiderstands diesem Oxidationsprodukt zugeschrieben. Die elektrische Leitfähigkeit wird dadurch negativ beeinflußt. Die Bildung des Chromoxids erfolgt bei Sauerstoffpartialdrücken von weniger als 10-18 bar. Diese Sauerstoffpartialdrücke sind während des Betriebs der Hochtemperatur-Brennstoffzelle in der Regel immer vorhanden.In the case of such a high-temperature fuel cell, direct contacting between the nickel network (or nickel network package) on one side and the bipolar plate (interconnector plate) made of CrFe5Y 2 O 3 l on the other side was previously selected. Experiments have now shown that an increased series resistance arises after a short period of operation on the fuel gas side. Said nickel network serves on the fuel gas side (anode side) of the high-temperature fuel cell as a contact between the bipolar plate and the solid electrolyte. The tests have now shown that in the case of the direct connection between the nickel network and the interconnector plate, an intermediate oxide layer, which is composed essentially of chromium oxide, appears after a short time. Since this chromium oxide layer has a higher resistance than the metals used, the increase in series resistance is attributed to this oxidation product. The electrical conductivity is adversely affected. Chromium oxide is formed at oxygen partial pressures of less than 10 -18 bar. These partial pressures of oxygen are generally always present during the operation of the high-temperature fuel cell.

Genauere Untersuchungen haben folgendes ergeben: Bisher wurde das Nickelnetz mittels Punktschweißens an der bipolaren Platte angepanktet. Die Schweißpunkte und auch die Kontaktpunkte werden während des Betriebs vom Chromoxid sozusagen unterwandert. Es liegt somit eine schlecht leitende Oxidschicht zwischen dem Nickelnetz und der Interkonnektorplatte aus CrFe5Y2O31 vor.More detailed investigations have shown the following: So far, the nickel network has been attached to the bipolar plate by means of spot welding. The welding points and also the contact points are, as it were, infiltrated by the chromium oxide during operation. There is therefore a poorly conductive oxide layer between the nickel network and the interconnector plate made of CrFe5Y 2 O 3 1.

Aufgabe der Erfindung ist es, eine Hochtemperatur-Brennstoffzelle der eingangs genannten Art derart zu verbessern, daß der erhöhte Serienwiderstand vermieden und eine hohe Leitfähigkeit auch über längere Zeit sichergestellt ist.The object of the invention is a high-temperature fuel cell to improve the type mentioned in such a way that the increased series resistance avoided and high conductivity is also ensured over a long period of time.

Der Erfindung liegt weiterhin die Aufgabe zugrunde, einen Hochtemperatur-Brennstoffzellenstapel mit mindestens einer solchen Brennstoffzelle anzugeben.The invention is also based on the object High temperature fuel cell stack with at least one to specify such a fuel cell.

Die Erfindung beruht auf der Überlegung, daß dieses erreicht werden kann, wenn die Bildung der besagten Chromoxid-Schicht zumindest weitgehend vermieden werden kann. The invention is based on the consideration that this is achieved can be when the formation of said chromium oxide layer can be at least largely avoided.

Die erstgenannte Aufgabe wird bei der eingangs genannten Hochtemperatur-Brennstoffzelle erfindungsgemäß dadurch gelöst, daß die bipolare Platte aus CrFe5Y2O31 auf der Brenngasseite mit einer Nickelschicht versehen ist, und daß das Nickelnetz auf dieser Nickelschicht mittels eines Punktschweißverfahrens elektrisch leitend befestigt ist.The first-mentioned object is achieved according to the invention in the aforementioned high-temperature fuel cell in that the bipolar plate made of CrFe5Y 2 O 3 1 is provided on the fuel gas side with a nickel layer, and in that the nickel network is attached to this nickel layer in an electrically conductive manner by means of a spot welding process.

Auch hier kann das Nickelnetz ein Nickelnetzpaket aus einem dünneren Nickel-Kontaktnetz und einem dickeren Nickel-Tragnetz sein.Here, too, the nickel network can consist of a nickel network package thinner nickel contact network and a thicker nickel support network his.

Weitere bevorzugte Ausführungsformen sind in den Unteransprüchen gekennzeichnet.Further preferred embodiments are in the subclaims characterized.

Bezüglich des Hochtemperatur-Brennstoffzellenstapels wird die genannte Aufgabe erfindungsgemäß dadurch gelöst, daß der Stapel eine Vielzahl übereinander angeordneter Verbundleiterplatten mit dazwischen liegenden Elektrolyten aufweist, wobei jeweils zwei benachbarte Verbundleiterplatten eine Hochtemperatur-Brennstoffzelle der vorstehend genannten Art bilden.Regarding the high temperature fuel cell stack, the mentioned object achieved in that the stack a large number of interconnected printed circuit boards with electrolytes in between, wherein two adjacent composite circuit boards each a high-temperature fuel cell of the type mentioned above.

Durch eine dünne Nickelschicht auf der bipolaren Platte (Interkonnektorplatte) wird eine bessere Anhaftung des Nikkelnetzes erreicht. Die beiden Materialien von Nickelnetz und Nickelschicht besitzen ähnliche Zusammensetzungen und zeigen somit eine sehr gute Verbindungsqualität. Beim Betrieb der Hochtemperatur-Brennstoffzelle erfolgt praktisch keine Unterwanderung der Schweiß- und Kontaktpunkte des Netzes mit einer Chromoxid-Schicht. Die anfängliche Leitfähigkeit des Verbunds bipolare Platte-Nickelschicht-Nickelnetz bleibt praktisch innerhalb der gesamten Betriebsdauer erhalten.Through a thin layer of nickel on the bipolar plate (Interconnector plate) will have better adhesion of the Nikkel network reached. The two materials from Nickelnetz and Nickel layers have similar compositions and show thus a very good connection quality. When operating the High-temperature fuel cells practically do not infiltrate the welding and contact points of the network with one Chromium oxide layer. The initial conductivity of the network bipolar plate-nickel-layer-nickel network remains practical received within the entire operating time.

Die Beschichtung der bipolaren Platte mit einer dünnen Nikkelschicht kann nach kostengünstigen Verfahren durchgeführt werden. Der Vorgang kann z.B. durch chemische oder galvanische Abscheidung erfolgen. Die Schichtdicke sollte dabei etwa 20 µm betragen. Und die Brenngasseite der bipolaren Platte sollte im Netzbereich vollflächig mit Nickel bedeckt sein. Coating the bipolar plate with a thin layer of nickel can be done by inexpensive procedures become. The process can e.g. by chemical or galvanic Separation. The layer thickness should be about Amount to 20 µm. And the fuel gas side of the bipolar plate should be completely covered with nickel in the mesh area.

Die Kontaktierung des Nickelnetzes mit der bipolaren Platte kann mit herkömmlichen Punktschweißverfahren durchgeführt werden.Contacting the nickel mesh with the bipolar plate can be done with conventional spot welding methods become.

Eine Untersuchung von Proben mit einer erfindungsgemäß Nikkelschicht ergab auch bei der Simulation des "Anfahrens" von Stack-Versuchen an stehender Luft eine beständige Kontaktverbindung des Nickelnetzes mit dem beschichteten CrFe5Y2O31-Material. Die Verbindung ist metallischer Natur. Die Bildung einer Zwischenschicht aus Chromoxid (Cr2O3) war bei den Proben nicht zu erkennen.An examination of samples with a nickel layer according to the invention also showed a permanent contact connection of the nickel network with the coated CrFe5Y 2 O 3 1 material when simulating the "start-up" of stack tests in standing air. The connection is metallic in nature. The formation of an intermediate layer of chromium oxide (Cr 2 O 3 ) was not evident in the samples.

Als besonderer Vorteil wird es angesehen, daß die elektrische Leitfähigkeit der Kontakte bipolare Platte-Nickelschicht-Nikkelnetz praktisch über die gesamte Betriebsdauer der Hochtemperatur-Brennstoffzelle beibehalten wird.It is considered a particular advantage that the electrical Conductivity of the contacts bipolar plate-nickel-layer nickel network practically over the entire operating life of the high-temperature fuel cell is maintained.

Ein Ausführungsbeispiel der Erfindung wird im folgenden anhand einer Figur näher erläutert. Die Figur stellt einen Ausschnitt aus einer Hochtemperatur-Brennstoffzelle 1 dar.An embodiment of the invention is described below a figure explained in more detail. The figure represents a section from a high-temperature fuel cell 1.

Nach der Figur ist eine bipolare Platte 2 (Interkonnektorplatte aus CrFe5Y2O31) mit einer Anzahl vom Betriebsmittel-Kanälen 4 versehen, die senkrecht zur Papierebene verlaufen. Diese Kanäle 4 werden mit einem Brenngas, wie Wasserstoff, Erdgas oder Methan, beschickt. Der untere Teil der Hochtemperatur-Brennstoffzelle 1 stellt die Anodenseite dar. Die Oberfläche 6 der bipolaren Platte 2 ist mit einer dünnen Nickelschicht 8 versehen. Die Dicke d dieser Nickelschicht 8 beträgt etwa 20 µm. Auf der Nickelschicht 8 ist ein Nickelnetz 10 durch Punktschweißen elektrisch leitend befestigt. Das Nickelnetz 10 ist hier ein Nickelnetzpaket, bestehend aus einem groben, dickeren Nickel-Tragnetz lOa und einem feinen, dünneren Nickel-Kontaktnetz lOb. An dieses Nickelnetz 10 grenzt über eine dünne Anode 11 ein Feststoff-Elektrolyt 12 an. Dieser Elektrolyt 12 wird nach oben von der Kathode 14 begrenzt. An die Kathode 14 schließt sich über eine Kontaktschicht eine weitere bipolare Platte 16 mit einer Anzahl von Betriebsmittel-Kanälen 18, von denen nur einer gezeigt ist, an. Die Betriebsmittel-Kanäle 18 verlaufen parallel zur Papierebene. Sie führen im Betrieb Sauerstoff oder Luft.According to the figure, a bipolar plate 2 (interconnector plate made of CrFe5Y 2 O 3 1) is provided with a number of operating device channels 4 which run perpendicular to the paper plane. These channels 4 are fed with a fuel gas, such as hydrogen, natural gas or methane. The lower part of the high-temperature fuel cell 1 represents the anode side. The surface 6 of the bipolar plate 2 is provided with a thin nickel layer 8. The thickness d of this nickel layer 8 is approximately 20 μm. A nickel network 10 is attached to the nickel layer 8 in an electrically conductive manner by spot welding. The nickel network 10 is here a nickel network package, consisting of a coarse, thicker nickel support network 10a and a fine, thinner nickel contact network 10b. A solid electrolyte 12 adjoins this nickel network 10 via a thin anode 11. This electrolyte 12 is delimited at the top by the cathode 14. A further bipolar plate 16 with a number of operating device channels 18, only one of which is shown, is connected to the cathode 14 via a contact layer. The equipment channels 18 run parallel to the paper plane. They carry oxygen or air during operation.

Die Einheit bestehend aus Kathode 14, Festkörper-Elektrolyt 12 und Anode 11 wird als Elektrolyt-Elektronen-Einheit (MEA) bezeichnet.The unit consisting of cathode 14, solid electrolyte 12 and anode 11 is used as an electrolyte-electron unit (MEA) designated.

Die in der Figur gezeigte Nickelschicht 8 verhindert die Bildung einer Chromoxid-Schicht zwischen der bipolaren Platte 2 und dem Nickelnetz 10 und sorgt damit für eine gleichbleibend gute elektrische Leitfähigkeit der Kontakte. Die Brennstoffzelle besitzt also einen geringen Serienwiderstand, der sich im Laufe der Betriebsdauer nicht erhöht.The nickel layer 8 shown in the figure prevents the formation a chromium oxide layer between the bipolar plate 2 and the nickel net 10 and thus ensures a constant good electrical conductivity of the contacts. The fuel cell therefore has a low series resistance, which is not increased during the operating period.

Mehrere solcher Brennstoffzellen können zu einem "Stack" oder Brennstoffzellen-Stapel zusammengefaßt werden.Several such fuel cells can form a "stack" or Fuel cell stack can be summarized.

Claims (4)

  1. High-temperature fuel cell with a bipolar plate (2) made from CrFe5Y2O31, the fuel-gas side of which has been provided with a nickel layer (8), in which, between the bipolar plate (2) on the fuel-gas side and a solid electrolyte (12), a nickel grid (10) has been secured in an electrically conducting manner on the nickel layer (8) by means of a spot welding process.
  2. High-temperature fuel cell according to Claim 1,
    characterized in that a chemical or electroplating method has been used to apply the nickel layer (8) to the bipolar plate (2).
  3. High-temperature fuel cell according to Claim 1 or 2,
    characterized in that the thickness (d) of the nickel layer (8) is about 20 µm.
  4. Stack of high-temperature fuel cells which has a large number of connector plates (2, 16) arranged one on top of the other with an electrolyte (12) situated therebetween, where each two adjacent connector plates (2, 16) form a high-temperature fuel cell according to any of Claims 1 to 3.
EP99952294A 1998-08-11 1999-08-05 High-temperature fuel cell with a nickel network on the anode side and high-temperature fuel cell stack having said cell Expired - Lifetime EP1114484B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE19836352 1998-08-11
DE19836352A DE19836352A1 (en) 1998-08-11 1998-08-11 High temperature fuel cell has a nickel net fixed in electrically conductive contact with a nickel layer on the fuel gas side of a bipolar plate to reduce chromium oxide layer formation
PCT/DE1999/002436 WO2000010214A2 (en) 1998-08-11 1999-08-05 High-temperature fuel cell with a nickel network on the anode side and high-temperature fuel cell stack having said cell

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EP1114484A2 EP1114484A2 (en) 2001-07-11
EP1114484B1 true EP1114484B1 (en) 2002-04-03

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AT (1) ATE215744T1 (en)
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WO (1) WO2000010214A2 (en)

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EP1173898A1 (en) * 1999-03-26 2002-01-23 Siemens Aktiengesellschaft High-temperature fuel cell
WO2001004981A1 (en) * 1999-07-09 2001-01-18 Siemens Aktiengesellschaft Electrical bonding protected against oxidation on the gas combustion side of a high temperature fuel cell
JP3841149B2 (en) * 2001-05-01 2006-11-01 日産自動車株式会社 Single cell for solid oxide fuel cell
DE10342161A1 (en) 2003-09-08 2005-04-07 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Electrical contacting for high-temperature fuel cells and method for producing such a contact
WO2009068674A2 (en) * 2007-11-30 2009-06-04 Elringklinger Ag Protective layers deposited without current
DE102007058907A1 (en) * 2007-11-30 2009-06-04 Elringklinger Ag Process to manufacture a solid oxide fuel cell with a steel substrate coated with metals from the transition group except chrome
DE102008036847A1 (en) * 2008-08-07 2010-02-11 Elringklinger Ag Fuel cell unit and method for making an electrically conductive connection between an electrode and a bipolar plate
ES2882477T3 (en) 2019-08-02 2021-12-02 Helmholtz Zentrum Hereon Gmbh System and procedure for thermal management of high temperature systems
EP3843189B1 (en) 2019-12-23 2022-09-21 Helmholtz-Zentrum hereon GmbH Apparatus for operating an exothermic hydrogen consumer with metal hydride storage
EP3843190B1 (en) 2019-12-23 2023-03-15 Helmholtz-Zentrum hereon GmbH Frost startable metal hydride hydrogen tank system

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DE4016157A1 (en) * 1989-06-08 1990-12-13 Asea Brown Boveri High temp. fuel cell stack - with cells series-connected by separator plates and elastic current collectors
EP0424732A1 (en) * 1989-10-27 1991-05-02 Asea Brown Boveri Ag Current conduction element for stacked hightemperature fuel cells and method of manufacture
JPH0536425A (en) * 1991-02-12 1993-02-12 Tokyo Electric Power Co Inc:The Alloy separator for solid electrolytic fuel cell and manufacture of the same
DE19517451A1 (en) * 1995-05-12 1996-05-23 Mtu Friedrichshafen Gmbh Fuel-cell stack assembly with bipolar metal sheets
AUPN876896A0 (en) * 1996-03-18 1996-04-18 Ceramic Fuel Cells Limited An electrical interconnect for a planar fuel cell
DE19649457C1 (en) * 1996-11-28 1998-06-10 Siemens Ag High temperature fuel cell with improved contact between anode and braid
DE19650704C2 (en) * 1996-12-06 2000-09-14 Forschungszentrum Juelich Gmbh Connection element for fuel cells

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US20010026882A1 (en) 2001-10-04
DE19836352A1 (en) 2000-02-17
ATE215744T1 (en) 2002-04-15
WO2000010214A3 (en) 2000-06-02
DE59901149D1 (en) 2002-05-08
EP1114484A2 (en) 2001-07-11
WO2000010214A2 (en) 2000-02-24
CA2340159A1 (en) 2000-02-24

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